This invention relates to the field of polymer film laminates and in particular, to a film laminate possessing an oriented polypropylene core layer faced on each side thereof with surface layers which are appropriate to the inside and the outside of a packaging film of this type. Oriented polypropylene packaging films are well known in the art. U.S. Pat. No. 4,659,612 describes a multi-layer film laminate which includes a core layer of oriented polypropylene, both surfaces of which carry a comparatively thin skin layer of oriented polypropylene containing an appropriate anti-block agent. One of the skin layers also has been compounded with a silicone oil in an amount such that when the film is rolled into a stock roll and subsequently unrolled, sufficient silicone oil is transferred to the opposite surface of the structure so as to adequately lower the coefficient of friction value of the surface.
U.S. Pat. No. 4,692,379 is directed to a multi-layer film structure also having a core layer of oriented polypropylene. However, on opposite surfaces of this core is laminated a heat sealable film structure, for example, an ethylene-propylene-butene-1 terpolymer. This terpolymer has incorporated therein an appropriate amount of an anti-block agent. One of these surface layers also has incorporated therein a silicone oil of a sufficient amount such that on rolling the film structure into a stock roll and subsequently unrolling the film sufficient silicone oil is transferred to the surface of the opposite skin layer. The amount of silicone oil transferred to the surface is such to significantly reduce the coefficient of friction value of this surface.